SENIOR RailCorp executives warned that continued cuts to maintenance funding would jeopardise the safety of the network a year before the O'Farrell government announced 450 jobs would be axed, leaked documents reveal.

The confidential report of an executive management meeting shows RailCorp was already struggling with funding cuts in February 2011, a month before the state election in which the O'Farrell government took office.

It had asked the then Labor government for a maintenance budget of $1.175 billion for the 2011-12 financial year. But the government offered only $1.049 billion - a shortfall of $126 million.

''Ongoing forward estimate reduction … will not allow the existing levels of safety and reliability to be maintained in the long term,'' the report warns.

Maintenance funding for 2011-12 ended up at $1.11 billion, higher than the proposed amount but less than initially requested and the same as the previous year.

This meant the maintenance budget was cut in real terms in the first year of the O'Farrell government when inflation was taken into account, reversing a trend of higher yearly spending on maintenance.

Last November, the Transport Minister, Gladys Berejiklian, announced that as part of the government's ''fixing the trains'' policy, 450 maintenance jobs, or 10 per cent of the workforce, would be cut from RailCorp.

The cuts would be achieved by merging smaller maintenance depots across the network to create larger ''centres of excellence'', Ms Berejiklian said.

The O'Farrell government's maintenance budget for the present financial year is $1.165 billion, still less than RailCorp's request of two years ago but a record high. However, this would include spending to build the new centres.

Separate documents obtained by Fairfax Media show the government plans to collapse 126 maintenance depots into six ''super depots'' and 17 satellite depots.

The national secretary of the Rail, Tram and Bus Union, Bob Nanva, said the documents were ''alarming''.

''RailCorp warned that track safety would be compromised by budget cuts almost two years ago, yet since then the government has only accelerated its program of cuts,'' he said. ''The wholesale axing of maintenance depots will gut RailCorp of the experience and knowledge needed to keep our rail network safe.''

Ms Berejiklian said: ''This is a Labor government document written two years ago. Any restructure and changes in responsibility across RailCorp are being reviewed by Australian Transport Safety Bureau commissioner and former head of the Independent Transport Safety Regulator Carolyn Walsh.''

The February 2011 document shows RailCorp was planning to delay refurbishing Tangara trains as one way of coping with its lower budget. But the document says deferring cosmetic maintenance on Tangaras were only short-term initiatives.